Since I'm not terribly familiar with XP and the resulting Admin rights I'm shackled with on this computer in my new classroom, I need you guys to tell me if my lack of rights would cause a problem.

I've been given a refurbished Dell. I considered looking up the specs and see how much I could upgrade the hardware, the CPU and RAM in particular. My plan was to upgrade the machine, and then put the original hardware back in before I left for the summer.

So the question is, changing the CPU and the RAM shouldn't cause any kind of updating that would require admin rights to the machine, correct?

I think as long as it's only that you should be all right.
But when you have the ability to change the hardware it shouldn't be a problem to boot the computer with live-cd that enables you to change the admin password.

Only problems would be if you had to manually install or update drivers, which you shouldn't. Windows should load drivers automatically.

Only if you upgrade other hardware should there be a problem, but as long as you're doing that you might as well use one of those boot tools to get the admin password or make yourself an admin account or something.

But if I changed the admin password, wouldn't the techs would know when they tried to login?

It's a school computer, and there's no case lock on it?

As long as you don't change the hard drive or replace the motherboard you shouldn't have an activation issue either.

That's the thing to watch out for. Not all processors and motherboards are made equal; you need to make absolutely certain that the CPU you buy will work in the machine.

Also, if you switch to/from a multicore/hyperthreading processor, you'll likely need to reinstall Windows because the two have different ACPI drivers and different schedulers, which is something Windows can't change on the fly.